This study quantifying the sensitivity and tolerance of fish species to stressor gradients in the Karun River basin (Western Iran) and to used this information to develop a fish-based tolerance index, the Karun Fish Tolerance Index (KFTI), that can serve as a practical management tool. We also tested if native, endemic, and nonnative fish species differ in tolerance to the range of stressors that occur in the Karun River system. The KFTI complements a multimetric index (KFMMI) based on the same data developed in a companion study. The two complementary fish-based indices developed based on this dataset, that is, KFTI (this study) and KFMMI (Zare Shahraki et al., 2022b) are now available for use by stakeholders, managers, and scientists to evaluate the quality of freshwater ecosystems in Iran and elsewhere. This dataset is not publicly accessible because: Data is the property of Swiss Leading House South Asia and Iran (ZHAW) and Isfahan University of Technology. It can be accessed through the following means: The data that support the findings of this study are available from the corresponding author (Andreas Bruder) upon reasonable request. Format: Physical habitat, landscape data, and water chemistry.

This dataset is associated with the following publication: Zare Shahraki, M., P. Fathi, E. Ebrahimi Dorche, J. Flotemersch, K. Blocksom, J. Stribling, and A. Bruder. Environmental impact assessment and conservation planning of a Middle-Eastern River basin using a fish-based tolerance index. River Research and Applications. John Wiley & Sons Incorporated, New York, NY, USA, 40(3): 411-424, (2024).